Brazilian protesters have come out in force at Rio+20 – the UN Conference on Sustainable Development, to demand that Iran release Christian Pastor Youcef Nadarkhani.

The protest was organized Brazilian Pastor Silas Malafaia and took place on Thursday in front of the Royal Tulip Hotel in Sao Conrado, in the South Zone of Rio de Janeiro. The protest location was chosen as Iranian President Mahmoud Ahmadinejad was staying at that hotel as a conference delegate.

Aiming to draw the attention of the Iranian president and the international press, protesters held banners that read "President Ahamdinejad free Pastor Youcef Nadarkhani! Religious Freedom in Iran now!"

An official letter was also delivered to the Iranian president, in which Brazilian Christian pastors made a plea for the life of Pastor Nadarkhani, who has been arrested and imprisoned in Iran. He has been accused of apostasy for having converted from Islam, and many fear he will face the death penalty.

"We, Christian pastors of Brazil, representing millions of evangelicals in our country, hereby appeal for the life of your co-citizen imprisoned, Mr. Youssef (sic) Nadarkhani, who has through the Internet sent out appeals for prayers on his behalf and on behalf his family."

"We evangelicals of Brazil, following the biblical principle of tolerance and above all the rights of free will, defend the rights of all Muslims who are presently living in Brazil to freely confess their faith and their culture. And, in the same way, we expect reciprocity of your government towards the Iranian Christians in your country."

Good diplomatic relations between Brazil and Iran are seen as hopeful for the efforts to release Pastor Nadarkhani.

According Jordan Sekulow, director of the American Center for Law and Justice (ACLJ) in the United States, who is monitoring the case, the only thing that can save the pastor is continued international pressure, particularly from countries such as Brazil that have close ties with Iran.

Iranian Pastor Youcef Nadarkhani, 34, has pastored for a network of house churches in the Middle East country. Before his arrest in 2009, he was the pastor of a 400 person congregation in the Gilan province.

Nadarkhani was arrested in October 2009 for protesting the mandatory teaching of Islam at his children's schools. His charges were later changed to apostasy and attempting to evangelize Muslims.